Well, it probably means what it says: File not readable (or specifically data not readable). The file is almost certainly really damaged and unrecoverable. Other than that of course the copy&paste could become corrupted by external interference like virus scanners....

Ok, thanks. I have been experiencing catasrophic failure with Illustrator. Now it doesn't mater what the file size is, nor wether or not I paste into a new document, Illustrator CS4 has crashed on me at least half a dozen times since 8AM (CDT). I have tried EVERYTHING as far as troubleshooting. Shut-down & "Safe Booted" my system. Verified Disks. Uninstall/re-install Illustrator. (Only illustrator is giving me issues, by the way.) Dumped the preferences. Cleared out misc. folders within the Library folder.

I am thinking about taking it into the shop to have the machine itself looked at. However, they may just tell me it's the program. Will updating this to CS5 help at all?

I was working with a file (with a lot of layers) that was 388 MB. It's normally not the issue. So I separated the file & tried to paste one/two images into a separate document. This knocked the file down to 1.8 MB. Thats when it crashed & said File not readable. Then I restarted & then it allowed me to work some more with the file, yet it crashed multiple times soon after when I would try to save or even print to a postscript.

I have asked around yesterday on this forum site, along with Apple's forum site & no one seems to be able to help. I really don't want to take this into the shop, as I don't like being at work without a computer to work on and I have a few hot projects. The apple forum suggested- as a last chance effort- to re-install OS X operating system. That will become very time consuming because I have at least 400 GB of stuff to back up on here.

When serious things happen, the following list of options may apply. In this case, only some of them are relevant, namely 4) and 6), but to rule out 5) you may try working with only Illy open and everything else shut down. 6) without the Cleaner Tool does not reset the preferences.

1) Close down Illy and open again;

2) Restart the computer;

3) Close down Illy and press Ctrl+Alt+Shift/Cmd+Option+Shift during startup;

I found a suggestion on a Graphic Design forum. They had suggested that I not "delete/reinstall preferences" but rather just "Reset" them. Ctrl+shift+alt+cmnd... hold these down while starting up Illustrator. That seems to be working thus far. ...almost like it's a brand new program

I did, however, have to reload any additional plugins I had & then go switch the ruler increments back to inches, but other than that... this seems to be working.

Actually, the solution was identical to this part of the list in post #3:

3) Close down Illy and press Ctrl+Alt+Shift/Cmd+Option+Shift during startup;

I ruled that out because in post #2 you wrote

I have tried EVERYTHING ... Dumped the preferences....

Ctrl+Alt+Shift/Cmd+Option+Shift is the standard way of deleting = resetting = dumping the basic preferences so I was convinced you had done that already (hence my suggestion to start with 4 and skip 1) - 3)).

as suggested in post # 3, you move all the preferences to another place so that they are reset to the defaults when you open Illy next time; this procedure is more thorough (and therefore capable of solving more issues) and reversible so you can get the preferences back if it does not help.

I'm sorry.. I when I said "Dumped preferences," I had meant that I Deleted them, not Reset them... sorry for any confusion Also.. I found the reset solution on a different forum earlier Friday afternoon. We left work early on Friday, due to the holiday, therefore I did not receive your suggestions until this morning.

Thanks everyone for your support with my issues It was greatly appreciated!